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I'm in a bit of a tight situation, as I need a new battery pack for an upcoming competition, so I've tried to make my own.

I put 7 of these: http://www.amazon.com/Rayovac-Alkaline-AA-Batteries-36-Pack/dp/B002M3TLGM in series to add up to 10.5V.

Would it be safe to draw 1.5A for ~10 minutes? I can't seem to find the exact datasheet for this battery.

Ryan
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  • It's in the datasheet. – Ignacio Vazquez-Abrams Dec 06 '14 at 21:12
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    Buy batteries with a datasheet, if you can't find it for those ones. – Leon Heller Dec 06 '14 at 21:20
  • Is 1.5A safe? More a less (by virtue of it being an alkaline battery). – Nick Alexeev Dec 06 '14 at 22:06
  • @NickAlexeev Since the graph shows data out to 1.1A, and I assume there is some safety margin, I would think it would be okay. Furthermore, the internal resistance is somewhere around 120 mΩ (the Rayovac datasheet didn't spec this, but both the Energizer and Duracell datasheets do), so 1.5² * 0.12 = 0.27 or 1/4 watt loss due to heat, so it may get warm but I don't think it will explode. – tcrosley Dec 07 '14 at 00:23
  • @tcrosley It looks more like the line for #815 goes out to 2A, unless my ability to read log axis is out of whack. – Nick Alexeev Dec 07 '14 at 01:28
  • @NickAlexeev You're perfectly right, I was thinking the right side of the graph was 2A instead of 10A. I'll update my answer. My earlier comment about the losses due to internal resistance of course are still valid. – tcrosley Dec 07 '14 at 04:18

1 Answers1

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In a Rayovac Application Note entitled "OEM Application Notes & Product Data Sheet -- Primary Batteries—Alkaline, & Heavy Duty", there is a graph on page 4 which lists the expected service life for various continuous mA drains of the battery. For the #815 AA Alkaline battery (dotted red line), the graph shows that you should be able to draw 1.5A for 0.7 hours or about 40 minutes, well beyond the 10 minutes you need.

enter image description here

Note that you can probably expect the voltage to drop to 1.2v fairly rapidly, since the internal resistance is around 120 mΩ so you will lose 0.18v just to that. The voltage will continue to drop down to below 1.0v at the end of the 10 minute period. So you will need more than 7 batteries if you require 10v for the entire 10 minutes.

Here is the link for the Rayovac datasheets

tcrosley
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